Final answer:
Polar bears interact with abiotic factors in various ways, but hunting for food involves biotic factors. They are well-adapted to the Arctic environment through insulation from thick fur and blubber, and they rely on sea ice for hunting seals. Melting sea ice affects polar bears the most as it directly impacts their ability to hunt and survive.
Step-by-step explanation:
The question posed is concerned with the types of interactions between polar bears and abiotic factors in the Arctic environment. Among the listed options, hunting for food is the only interaction that does not solely involve abiotic factors, as the act of hunting intrinsically involves biotic components, namely, the prey being hunted which in most cases for polar bears are seals. Polar bears do adapt to cold temperatures, seek shelter from extreme weather, and swim in icy waters; these are all interactions with abiotic factors like temperature, weather, and water. These adaptations include having thick fur and a layer of blubber for insulation against the cold Arctic temperatures.
Regarding the second part of the question about the effects of melting sea ice, polar bears would be the most affected among the choices provided, because their hunting strategy for seals depends heavily on the presence of sea ice. Grizzly bears, black bears, and koalas are not dependent on sea ice for their survival to the same extent as polar bears. It’s also worth noting that koalas are not native to the Arctic and they do not interact with sea ice in their environments.
The white fur of polar bears is an evolutionary adaptation that provides camouflage in the Arctic snow and ice, which helps them remain undetected by prey when hunting. It is an example of how species adapt characteristics that help them survive in their specific habitats.
Finally, although polar bears can maintain their body temperature due to their adaptations, melting sea ice poses a significant threat to their ability to hunt and survive, making them highly susceptible to changes in their Arctic ecosystem.